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Idle RPM & wiper blade queries


Well-known member
24 Mar 2004
Great Forum. I've been checking in for several months now and have found them extremely useful, especially while tracking down my current car a 993 Targa which I purchased 1 month ago. Having previously owned a Boxster S (no hairdresser jokes please) it has taken me a while to adjust to the 993 (offset pedals, etc) but now that I have I love it too bits. However, there are a couple of questions that have been niggling me and I'm hoping someone can answer:

1. When the engine is warm and idling the oil pressure is just below 2 bar and RPM 800'ish, both with very very slight fluctuations. But about every minute or so (or if I increase the heater fan speed) the pressure/RPM will drop (i.e. RPM = 700) then increase (i.e. RPM = 1000) before settling back to its original position. Is this normal or should the engine idle smoothly all the time? FYI - I have the AC on all the time if this makes any difference.

2. The first time I took the car out in the rain I noticed that the top (18") wiper blade smeared rain across the driver's side of the windscreen as it came to rest. So out I went and bought two new Bosch wiper arms (15" & 18") thinking that this would solve the problem. But it is exactly the same. Both of the blade ends do not make full contact when in the parked position, I tryed bending them slightly but no joy. Is this one of the 993's idiosyncrasies or am I missing a trick. The passenger side clears perfectly!

Any help would be appreciated.


Migration info. Legacy thread was 14884

I had exactly the same issues with my 993. Even without a/c on, occasionally the idle speed would settle at around 1000 rpm, ultimately coming to rest within a minute or so at 800 rpm. Again, I also changed the wiper arms and blades to try to clear the screen more effictively but to no avail. I've only owned one 993, so perhaps it's not definite, but I think this is a 993 idiosyncrasy. Mine always left a smear of water at about eye level arcing across the drivers side.

Enjoy the car.

Migration info. Legacy thread was 14885
Hi Jon,

I just joined the forum too and also just got myself a 993 C4.

I have the same two problems as you. The wipers I think are a 911 trait, I changed mine and the drivers one still misses the last few inches.

I took my car to Northway near Reading (what good blokes) and they reckon my Idle Stabiliser Valve is knackered. A new one is over £200, but I'm still searching.

Hope it helps,


Migration info. Legacy thread was 14924

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